To discover what true repentance is, I shall first show what it is not. There are several deceits of repentance which might occasion that saying of Augustine that 'repentance damns many'. He meant a false repentance; a person may delude himself with counterfeit repentance.
1. The first deceit of repentance is legal terror
A man has gone on long in sin. At last God arrests him, shows him what desperate hazard he has run, and he is filled with anguish. Within a while the tempest of conscience is blown over, and he is quiet. Then he concludes that he is a true penitent because he has felt some bitterness in sin. Do not be deceived: this is not repentance. Ahab and Judas had some trouble of mind. It is one thing to be a terrified sinner and another to be a repenting sinner. Sense of guilt is enough to breed terror. Infusion of grace breeds repentance. If pain and trouble were sufficient to repentance, then the damned in hell should be most penitent, for they are most in anguish. Repentance depends upon a change of heart. There may be terror, yet with no change of heart.
2. Another deceit about repentance is resolution against sin
A person may purpose and make vows, yet be no penitent. 'Thou saidst, I will not transgress' (Jer. 2.20). Here was a resolution; but see what follows: 'under every green tree thou wanderest, playing the harlot'. Notwithstanding her solemn engagements, she played fast and loose with God and ran after her idols. We see by experience what protestations a person will make when he is on his sickbed, if God should recover him again; yet he is as bad as ever. He shows his old heart in a new temptation.
Resolutions against sin may arise:
(1) From present extremity; not because sin is sinful, but because it is painful. This resolution will vanish.
(2) From fear of future evil, an apprehension of death and hell: 'I looked, and behold a pale horse: and his name that sat on him was Death, and Hell followed with him' (Rev. 6.8). What will not a sinner do, what vows will he not make, when he knows he must die and stand before the judgmentseat? Selflove raises a sickbed vow, and love of sin will prevail against it. Trust not to a passionate resolution; it is raised in a storm and will die in a calm.
3. The third deceit about repentance is the leaving of many sinful ways
It is a great matter, I confess, to leave sin. So dear is sin to a man that he will rather part with a child than with a lust: 'Shall I give the fruit of my body for the sin of my soul?' (Mic. 6.7). Sin may be parted with, yet without repentance.
(1) A man may part with some sins and keep others, as Herod reformed many things that were amiss but could not leave his incest.
(2) An old sin may be left in order to entertain a new, as you put off an old servant to take another. This is to exchange a sin. Sin may be exchanged and the heart remained unchanged. He who was a prodigal in his youth turns usurer in his old age. A slave is sold to a Jew; the Jew sells him to a Turk. Here the master is changed, but he is a slave still. So a man moves from one vice to another but remains a sinner still.
(3) A sin may be left not so such from strength of grace as from reasons of prudence. A man sees that though such a sin be for his pleasure, yet it is not for his interest. It will eclipse his credit, prejudice his health, impair his estate. Therefore, for prudential reasons, he dismisses it.
True leaving of sin is when the acts of sin cease from the infusion of a principle of grace, as the air ceases to be dark from the infusion of light.